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Need Solution for R.D.Sharma Maths Class 12 Chapter 30 Probability  Exercise Multiple Choice Questions  Question 45 Maths Textbook Solution.

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Answer:(b)

Hint: You must know the rules of finding probability.

Given: Bag – (5 red, 3 blue balls)

3 balls are drawn at random without replacement

Solution: Red balls = 5=P\left ( R \right )

Blue balls = 3=P\left ( B\right )

P (getting exactly one red ball)=P(R / B \cap R)+P(B / R \cap B)+P(B / B \cap R)

=P(R) \times P\left(\frac{B}{R}\right) \times P\left(\frac{B}{R \cap B}\right)+P(B) \times P\left(\frac{R}{B}\right) \times P\left(\frac{B}{B \cap R}\right)+P(B) \times P\left(\frac{B}{B}\right) \times P\left(\frac{R}{B \cap B}\right)

\begin{aligned} &=\left(\frac{5}{8} \times \frac{3}{7} \times \frac{2}{6}\right)+\left(\frac{3}{8} \times \frac{5}{7} \times \frac{2}{6}\right)+\left(\frac{3}{8} \times \frac{2}{7} \times \frac{5}{6}\right) \\ &=\frac{5}{56}+\frac{5}{56}+\frac{5}{56} \\ &=\frac{15}{56} \end{aligned}

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